The Camaro LS3 crate engine makes the LS series of engines legit. Up until now, you had to either spend ahoy on the gigabuck LS7, be happy with the iron 6.0L and its weird truck accessory drive, or strip down a pricey LS2 Corvette to get the coveted factory 4.00-inch-plus small-block bore size. For about $6,500, the new Camaro LS3 crate engine packs a 4.065-inch bore and matching performance cylinder heads and makes 430 hp and 424 lb-ft from the factory. This thing is such a good deal, you have to pay attention. The power potential of the LS3 crate engine comes from its ability to use the L92 cylinder head port design. We've tested this head before on a stock 6.0L and made 550 hp with a cam swap, so we know it works. We wanted to use this head on other LS-series engines like the LS1 (5.7L) or LM4 (5.3L), but the 2.165/1.59-inch valves require at least a 4.00-inch bore to clear the block and need the 4.065-inch LS3 bore size to be really happy. In addition to the base LS3, there are two variations of the LS3 crate engine also available. The LS3-based LS376 has a Hot cam and is rated at 480 hp. Add a single-plane GM intake and the ASA Hot cam, and GM claims the LS376 will make 515 hp and 469 lb-ft with a GM competition single-plane carbureted intake and a 770-cfm Holley. Remember, this engine is only 376 ci. If you go for the base LS3, you get a cast-aluminum block with iron cylinder liners, six-bolt cross-bolted main caps, and the L92 heads. The cylinder liners are designed for the stock 3.600-inch stroke, but it is possible to go to 4.00 inches. With the maximum overbore of 0.030, the block has the potential for 421 inches using an aftermarket rotator assembly. The cam is a hydraulic roller with 204/211 degrees of duration at 0.050 with 0.551/0.522 lift. The heads have a 68cc chamber and with the hypereutectic aluminum pistons yield a 10.7:1 compression ratio, so the engine needs 92- octane pump gas. The intake and drive-by-wire throttle body are included, but you'll need to buy the GM pedal assembly. GM offers an LS3 controller to run the system in everything from a street machine to a street rod. Head Flow We've tested the L92 port before on a different flow bench and our published numbers are slightly higher than the ones provided by GM below. The GM tests were performed with a 4.065-inch bore plate. The crankshaft on the LS3 is nodular iron instead of forged steel like the LS7 or LS9. The main journals are 2.56 inches and the rod journals are 2.100. All 5.3L to 6.2L LS engines use 6.067-inch connecting rods made of powdered metal. The crankshaft on the LS3 is nodular iron instead of forged steel like the LS7 or LS9. The If you are going to run a manual transmission, you will need a flywheel because the LS3 comes with a flexplate for the Corvette. McLeod offers a complete flywheel, clutch, and pressure plate to mate any early four-speed transmission to your LS-swapped car. If you are going to run a manual transmission, you will need a flywheel because the LS3 co The cylinder heads make the LS3, and there are a few factory options to add more power. As delivered, the LS3 castings have the L92 port. To review, the LS1 has the cathedral port that is tall and thin and worked great for the small-bore 5.7L engine. The next design was for L92-powered trucks, LS3 (Z06) Corvettes, and the new Camaro. The L92 intake port is 260 cc and resembles a big-block Chevy rectangular port. According to GM numbers, it flows 294/183 cfm at 0.500 lift. The cylinder heads make the LS3, and there are a few factory options to add more power. As 1 | 2 | 3 | » | View Full Article By Douglas R. Glad Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!